Planner: Add billable state to historical data

[Former user]

Please, add billable attribute to historical data.

Billable attribute is part of an Employee. It means a person is billable at the moment. But person could change billable state. For example, a person was an engineer and become a manager. So, for this case there is no information about billable state for historical data and it will be updated according to a current state (manager, not billable) even for period when the person was an engineer (billable). Please, add billable attribute to historical data as well.

Ideally it would be great to know not only flag but quantity of available hours for staffing. For example, principals should spent 0.5 of their fte to projects. So, a full-time principal is 20 hours billable.

Thanks!